The present invention relates to the field of integrated circuits, their manufacture, design, and operation. More specifically, in one embodiment the invention provides an improved method and device for testing integrated circuits in which the test system is qualified without the presence of an integrated circuit device.
Integrated circuit test systems are well known to those of skill in the art and are widely utilized in the integrated circuit manufacturing process. In a typical manufacturing process integrated circuit devices are formed on a wafer. A first test step is used to test the devices after fabrication on the wafer. The wafer is then diced and the individual integrated circuits are placed in packages. A second test step is then performed to test the fully packaged devices.
In a typical test system carefully selected signals are applied to the wafer probe leads or to the package leads of the device under test (DUT), and the response of the integrated circuit to these signals is monitored. The signals applied to the leads are referred to as "vectors" or "test vectors."
As integrated circuits are improved it is necessary to formulate new test vectors to apply to the improved integrated circuits. For example, as a microprocessor moves from one generation to another, it typically will increase in complexity. Accordingly, it is necessary to develop new test vectors and software for monitoring the response to the test vectors for each generation of microprocessors.
The conventional processes, however, are not desirable. As recognized herein, conventional processes result in long lead times for integrated circuit design and manufacturing. Specifically, the invention herein recognizes that it is extremely inefficient to wait for the first device to be manufactured before the test vectors for a test system may be utilized or tested. Since the test vectors often do not correctly or fully test the device, it is necessary after the first devices are fabricated to modify the test vectors. This leads to longer cycle times for developing and manufacturing integrated circuits.
From the above it is seen that an improved method of manufacturing integrated circuits is needed.